Research On A High-speed Permanent Magnet Generator And A Convertor Used In Aviation Power Supply

Considering the issues of difficulty of current commutation and arc eliminationdue to thin high altitude environment dielectric constant decreased, the reliability oftraditional brush DC generator used in aircraft is low. In order to solve the problemsabove, in this paper, the scheme with a high speed permanent magnet synchronousgenerator attached to an AC/DC power converter have been proposed. Thepermanent magnet synchronous generator improve the reliability of the system dueto it does not have brush, commutator, collector ring, and field winding. Thepermanent magnet synchronous generator has the advantages of small size, simplemechanical structure, light weight, and the shaft can be direct driven by primemover, it improve efficiency and reduce the weight of the power generation systemdue to the middle variable speed link has been canceled. In this paper, the studiesundertaken by electromagnetic design of the high-speed permanent magnetsynchronous generator, embedding dual windings, short circuit analysis andcalculation, major loss calculation, normal and short circuit temperature risecalculation and power converters and other aspects.Firstly, generator material, rotor magnetic circuit path, the number of slots andpoles, manner of embedded-line have been compared and selected based on theanalysis of the given targets and requirements of the aviation generator, while theinductor parameters were calculated at the same time. The generator load and loadcharacteristics have been analyzed on the basis of the initial structure parameters,and some major parameters have been optimized in order to achieve more desirableproperties to meet the performance. Since the generator require short-circuitperformance, the permanent magnet synchronous generator short-circuit transientprocess have been taken calculated both by analytical method and the finite elementmethod.Secondly, according to the electromagnetic calculations and the correspondinganalytical formula under different speed and working conditions, the armaturecopper loss, stator core loss, the rotor eddy current loss and rotor wind friction losshave been obtained. On basis of losses calculation, the model of three-dimensionaltransient thermal calculation have been established, transfer boundary conditions,convection heat coefficient and thermal conductivity coefficient are defined by theknowledge of Heat Transfer, and the heat and the generator temperature rise arecalculated on the normal working and short-circuit state.Finally, AC/DC dual channel power converter topology for simulation have been established, harmonic currents in three-phase uncontrolled bridge rectifier areeliminated by filter, and some experiments of the power converter have been takenwhen generation working on low speed.